ParentNode inherits from ChildNode and adds the capability of having child
nodes. Not every node in the DOM can have children, so only nodes that can
should inherit from this class and pay the price for it.

ParentNode, just like NodeImpl, also implements NodeList, so it can
return itself in response to the getChildNodes() query. This eliminiates
the need for a separate ChildNodeList object. Note that this is an
IMPLEMENTATION DETAIL; applications should _never_ assume that
this identity exists. On the other hand, subclasses may need to override
this, in case of conflicting names. This is the case for the classes
HTMLSelectElementImpl and HTMLFormElementImpl of the HTML DOM.

While we have a direct reference to the first child, the last child is
stored as the previous sibling of the first child. First child nodes are
marked as being so, and getNextSibling hides this fact.

Note: Not all parent nodes actually need to also be a child. At some
point we used to have ParentNode inheriting from NodeImpl and another class
called ChildAndParentNode that inherited from ChildNode. But due to the lack
of multiple inheritance a lot of code had to be duplicated which led to a
maintenance nightmare. At the same time only a few nodes (Document,
DocumentFragment, Entity, and Attribute) cannot be a child so the gain in
memory wasn't really worth it. The only type for which this would be the
case is Attribute, but we deal with there in another special way, so this is
not applicable.

This class doesn't directly support mutation events, however, it notifies
the document when mutations are performed so that the document class do so.

WARNING: Some of the code here is partially duplicated in
AttrImpl, be careful to keep these two classes in sync!

fNodeListCache

ParentNode

No public constructor; only subclasses of ParentNode should be
instantiated, and those normally via a Document's factory methods

ParentNode

public ParentNode()

Constructor for serialization.

Method Detail

cloneNode

public org.w3c.dom.Node cloneNode(boolean deep)

Returns a duplicate of a given node. You can consider this a
generic "copy constructor" for nodes. The newly returned object should
be completely independent of the source object's subtree, so changes
in one after the clone has been made will not affect the other.

Example: Cloning a Text node will copy both the node and the text it
contains.

Example: Cloning something that has children -- Element or Attr, for
example -- will _not_ clone those children unless a "deep clone"
has been requested. A shallow clone of an Attr node will yield an
empty Attr of the same name.

NOTE: Clones will always be read/write, even if the node being cloned
is read-only, to permit applications using only the DOM API to obtain
editable copies of locked portions of the tree.

getChildNodes

public org.w3c.dom.NodeList getChildNodes()

Obtain a NodeList enumerating all children of this node. If there
are none, an (initially) empty NodeList is returned.

NodeLists are "live"; as children are added/removed the NodeList
will immediately reflect those changes. Also, the NodeList refers
to the actual nodes, so changes to those nodes made via the DOM tree
will be reflected in the NodeList and vice versa.

In this implementation, Nodes implement the NodeList interface and
provide their own getChildNodes() support. Other DOMs may solve this
differently.

replaceChild

Make newChild occupy the location that oldChild used to
have. Note that newChild will first be removed from its previous
parent, if any. Equivalent to inserting newChild before oldChild,
then removing oldChild.

getTextContent

This attribute returns the text content of this node and its
descendants. When it is defined to be null, setting it has no effect.
When set, any possible children this node may have are removed and
replaced by a single Text node containing the string
this attribute is set to. On getting, no serialization is performed,
the returned string does not contain any markup. No whitespace
normalization is performed, the returned string does not contain the
element content whitespaces . Similarly, on setting, no parsing is
performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node
depending on its type, as defined below:

Node type

Content

/**
This attribute returns the text content of this node and its
descendants. When it is defined to be null, setting it has no effect.
When set, any possible children this node may have are removed and
replaced by a single Text node containing the string
this attribute is set to. On getting, no serialization is performed,
the returned string does not contain any markup. No whitespace
normalization is performed, the returned string does not contain the
element content whitespaces . Similarly, on setting, no parsing is
performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node
depending on its type, as defined below:

setTextContent

This attribute returns the text content of this node and its
descendants. When it is defined to be null, setting it has no effect.
When set, any possible children this node may have are removed and
replaced by a single Text node containing the string
this attribute is set to. On getting, no serialization is performed,
the returned string does not contain any markup. No whitespace
normalization is performed, the returned string does not contain the
element content whitespaces . Similarly, on setting, no parsing is
performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node
depending on its type, as defined below:

getChildNodesUnoptimized

protected final org.w3c.dom.NodeList getChildNodesUnoptimized()

Create a NodeList to access children that is use by subclass elements
that have methods named getLength() or item(int). ChildAndParentNode
optimizes getChildNodes() by implementing NodeList itself. However if
a subclass Element implements methods with the same name as the NodeList
methods, they will override the actually methods in this class.

To use this method, the subclass should implement getChildNodes() and
have it call this method. The resulting NodeList instance maybe
shared and cached in a transient field, but the cached value must be
cleared if the node is cloned.

normalize

public void normalize()

Override default behavior to call normalize() on this Node's
children. It is up to implementors or Node to override normalize()
to take action.